A Little Science Project: Growing Crystals

My kids recently grew salt crystals using colored salt water on a sponge, and the ALEX Kid Concoctions Grow a Crystal Dino set was a great way to expand their understanding of crystals and how they form!

The set comes with a small pouch of crystal liquid and two trays to hold a cardboard dinosaur and two cardboard trees. My four-year-old and six-year-old worked together to set it up.

Once it was put together, it was time to hypothesize about what would happen when we added the crystal liquid.

They looked at the clear liquid, and decided that nothing would happen.

We added the liquid around 2:12pm, and they immediately pointed out that they were correct – indeed, nothing had happened.

Then they noticed that the cardboard was absorbing the liquid, and that – as a result – the dyes in the cardboard were starting to bleed a bit. Around 2:52pm, we noticed that our first cluster of crystals had appeared, on the tree next to the dinosaur:

By 3:43pm, we had crystals on both trees, and several on the dinosaur as well:

Here is the yellow and orange tree at 6:36pm, with many more crystals:

I’m afraid that’s as far as that tree got – soon afterwards it was knocked over by a child. The fragile crystals fell off, and the cardboard was too wet to stand back up on its own. The remaining dinosaur and tree survived, however – here they are at 8:37pm:

And, almost exactly 12 hours later, at 8:48am:

This was such a fun experiment for my kids! They enjoyed watching the crystals grow, and were surprised to see that they absorbed the dye from the cardboard. The next morning they noticed that the liquid was completely gone, and that the now-dry crystals were a slightly lighter color than they had been the night before (when they were still damp).

They learned that these crystals grow much faster than our table salt crystals – it took us a couple days to see any salt crystals at all, and even after a week we only had very small salt crystals. These crystals started growing within forty minutes of being started – and, once started, they multiplied quickly.

Eventually, the dinosaur got knocked over, and the crystals fell off. The kids enjoyed exploring the texture of the crystals (kind of like cotton balls and kind of like Styrofoam, they decided), and they learned that the crystals were very fragile – easily crushed, and easily broken apart – much more fragile and much softer than the slower-growing salt crystals.

They also noticed that the dinosaur and tree were a lighter color than they had been when we started the experiment, because some of the dye had gone into the crystals. After playing with the crystals for a while, they gathered them all together, and were able to crush them into a tiny little ball. My six-year-old thought that the crushed crystals looked like tiny pieces of chalk.

Simple experiments like this are the perfect opportunity for kids to practice making hypotheses, testing them out, and learning through observation. The main takeaways my kids got from this experiment were that liquids can turn into solids, and that things aren’t always what they seem (the Crystal liquid looked like water, to them). There was also something enchanting in seeing a spiky dinosaur turn into a big puffball!